Abstract
Abstract
High-strength residual heat treatment steel bar was tested with welding thermal simulation in Gleeble 3500. Effect of heat input on the microstructure, impact toughness and microhardness of weld heat-affected zone (HAZ)was studied. The results show that with the increase of t8/5, microstructure of coarse grain heat-affected zone (CGHAZ)transforms into granular bainite and pearlite in stead of ferrite, feather-like upper bainite and strip-like lower bainite, HAZ impact value increases firstly then decreases and reaches maximum at t8/5= 100s and the hardness decreases. And when t8/5 increased to 60s there were only ferrite and pearlite in the microstructure of CGHAZ. The impact energy of high-strength residual heat treatment steel bar would be at the range of a good level for physical production with the range of t8/5 from 20s to 300s.
Subject
General Physics and Astronomy
Reference6 articles.
1. A modified analytical approach for modelling grain growth in the coarse grain HAZ of HSLA steels[J];Shome;Scripta Materialia,2004
2. Developmentsituations of LNG terminals in China[J];Lina;Oil & Gas Storage andTransportation,2016
3. Evaluation of dislocation density by local grain misorientation in deformed metals[J];Yang;Transactionsof Materials and Heat Treatment,2014